There is so such thing as high def DVD <yet>
There are some HD blu-ray designs floating around Japan, (very expensive) but there is not much content to watch on them yet.
True HD DVD players will be released in the US next year, but they will be very expensive.
Content will be scarce for the first several years as movie studios have an almost pavlovian response to new technologies. (which is to fight it in the name of copyright protection)
DVI will do you no good if your display does'nt have a DVI input
DVI will do you little good even if your display has a DVI input because there is an additonal digital to analog conversion at the disply which can mess with the signal (certain plasma displays with DVI are the exception)
The vast majority will be better off with a quality progressive scan DVD player with analog component outputs.
So this is not really a deal.
To learn more check out,
www.avsforum.com